Usually I am deeply suspicious of anything that comes out of a packet. However, Maharaja's Choice dahl makhani is completely delicious and also seemingly nutritious. I RECOMMEND IT!
It's not very hot at all (a tiny little bit, but if I can handle it I think everyone can :) -- if you made it yourself it'd be mostly tomatoes, ginger, garlic, coriander, cumin, nutmeg and cinnamon, and chilli (to taste :p).
I love Indian food too, though I'm like you -- I really have to avoid spicy stuff or I'm up all night drinking milk to get rid of the burning ;)